Bending machine



July 3, 1928.

H. E. FRENTZEL BEDDING momma 'Filed rep. 2:. 1926 s Sheets-Shet =1 11 ATTORNEY July 3, 1928. 1,676,215

H. E. FRENTZEL BENDING MACHINE Filed Feb. 23,.1926 3 Sheets-Sheet 3 nan i I K QQQQWQQ INVENTOR. fli/P/mffkfivrza.

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Patented UNITED STATES PATENT. OFFICE.

HERMAN E. FRENTZEL, 0F MILWAUKEE, WISCONSIN, ASSIGNOR TO THE FALK COR- PORATION, 0F MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

BENDING MACHINE.

Application filed February 23, 1926.v Serial, No. 89,890.

' This invention relates to bending "machines for use primarily in bending metal strips and the like into zigzag form.

One object of the present invention 1s the provision of an apparatus for bending metal strips into zigzag forln'with the several limbs or 'convolutions thereof lying in a substan-.

tially cylindrical surface of definite curvature. Such an apparatus may be used to particular. advantage in the manufacture of curved gridlike springs such as are employed for connecting the driving and driven coupling disks in a resilient coupling of the type described in the patent to James Bibby N 0. 1,391,713, issued September 27, 1921.

Other objectsand advantages will appear from the following description of an illustrative embodiment of the present invention.

In the drawings:

Figure 1 is a side elevation of an apparatus for producing springs of the form shown in Fig. 6.

Fig. 2 is a sectional view on a larger scale of the bending machine shown in Fig. 1.

Fig. 3 is a horizontal sectional View of the bending machine. i

Figs. 4. and 5 are fragmentary plan views of the rotating table shown in Fig. 3, respectively illustrating two extreme working positions thereof.

Fig. 6 is a perspective view of a curved grid-like spring produced by this apparatus. The apparatus selected for illustration comprises a bending machine having a sub stantially round base 10, in the form of a hollow casting, with a goose-neck 11 rising from the side thereof and overhanging the same. A substantially circular casting 12 of hollow form, fixed to the top of the base 10, constitutes a support for a horizontal ring 13 rotatable therein. A circular table 16, overlying the casting 12, is formed witha reduced portion 17 seated in the ring 13, and fixed thereto by any appropriate means such as screws 18, so as to rotate therewith.

The table 16, and consequently the ring 13, are centered by a series of anti-friction rollers 19 disposed within a horizontal race-way .20 encircling the table within the casting 12. The table 16 carries a depending leg 22, fixed thereto, and provided at the lower end thereof with a reduced portion 23, fitted for rotation within a bore 24 in the center of the bottom of the base 10. The table and ring are rotated by any appropriate means such as a worm 25 in mesh with a worm groove 26 formed about the periphery of the ring 13. The worm 25cis formed on a horizontal shaft 27 journaled in the casting 12, and driven by an electric motor. 28 through appropriate gearing 29.

The top of the table 16 is of curved convex form and is provided with a'transverse opening 30 forming a guideway for an oscillatable head 31, fitted therein. The head 31 is removably fixed by screws 32 or otherwise to i the upper end of-a lever 33, rockably mounted upon a bolt 34, extending through oneofa series of holes 35 in the lever into the corresponding hole of a like series formed in the leg 22. By projecting the bolt 34 through one or another of the holes 35 the fulcrum point of the lever may be varied, so as to permit the head 31, carriedthereby, to oscillate through an arc of greater or less radius, as the character of the work requires. The lever 33 is. actuated and controlled by any appropriate means such as a screw 36, threaded through a nut 37, rockably supported in a well known manner within the lever.- The screw 36 is swiveled adjacent one end in a block 38 rockably supported at one side of the table 16. The screw is provided with a hand wheel 39 or other convenient operating operates with the sockets 40 to accurately cen-- ter and releasably retain the head 31in any of a plurality of positions into which it is ad-- justed during operation. Any appropriate means such as a hand lever 42 mounted on the table may be employed for retracting the pin 11.

The head 31 shown is curved longitudinally the degree of curvature depending upon the degree of curvature desired in the finished product. The head isprovided witha longitudinal series of transverseslots 43, each slot extending downwardly into the head along a radius of curvature thereof. The slots 43, are shaped to receive a cor responding series of plugs or mandrels 44 about which the work is'bent and whose shape determines the shape of the convolutions of the finished product. The thickness of the walls 45 between successive slots is substantially equal to the thickness of the material acted upon, and, as indicated m Fig. 2, the upper end of each of the several plugs is thickened so as to bear against the next adjacent plug so that a groove is formed between each pair of plugs a for snugly housing the material operated upon. t will be noted that each plug 44 extends. upwardly from the head 31 along a radius of curvature thereof. The head 31 is further provided at one end with a permanent upright end plate 46 for cooperat1on with the end" plug 44 of the series.

Provision is preferably made for firmly holding each plug 44 in its socket as the work is bent thereabout'. In the machine shown this is accomplished by the use of a plunger 47 mounted for vertical reciprocation within the end 48 of the goose-neck '11. The plunger 47 is hollow and of cylindrical form. The upper end of the plunger is covered by a housing 48' fixed to the goose-neck. A stationary piston 49, closely fitted withinthe plunger 47, is supported by a hollow rod 50, fixed at its upper end in the housing 48'. A coil spring 51 surrounding the rod 50 'and confined between the piston 49 and a housing 52, carried by the plunger, yieldably retains the plunger n the upper position shown in Fig. 2. Fluid pressure from a pipe 53 may be admitted through the rod 50, to the bottom face of the piston 49 to force the plunger down. Fluid pressure is-supplied to pipe 53 from any appropriate source under the control of mechanism to be later described. The plunger 47 may also be operated by hand, and for this purpose a vertical rack 54 is fixed to one side thereof. The rack meshes with a pinion 55, fixed to a horizontal shaft 56 journaled in the goose-neck, and actuated by an appropriate handle 57 shown in Fig; 1. The plunger 47 is preferably provided with a plug engaging element 58 rotatable in the end thereof. The element 58 shown is provided witha projection 59 adapted, when the plunger 47 is lowered, to engage the exposed face 60 of the coacting plug 44 to hold the same firmly against the next adjacent in dotted lines in Fig. 2.

A pair of hammers are preferably provided for striking the material after each bending operation to drive the same squarely against the side of the plug. These hamplug, as indicated .mers are arranged at opposite sides of the head 31 .and each includes a lever 61,

mounted to swing upon a vertical pivot 62,

supported. by a bracket 63 fixed to and depending from the goose-neck 11. (See Figs. land 2.) Each lever '62 carries a striker head 64 and is actuated'by any appropriate means such as a handle 65.

During the bending operation the strip of metal operated upon extends laterally drum 67 rotatablv supported between brack- 'ets 68 carried by an upright frame 69. A weight 70 fixed to the cable 66 tends at all times to rotate the drum 67 in such direction as to tension the metal strip. A dog 71 pivotally supported at one end upon an upright lever 72, and cooperating with a ratchet wheel 73 on the end of the drum 67 normally prevents rotation of the drum under the influence of the weight. The lever 72 is mounted at its lower end upon a fixed horizontal pivot 74 and is connected at its upper end to a piston rod 75, connected with a piston 76 in a cylinder 77, rockably supported in the frame 69.. The piston 76 is actuated by fluid pressure delivered to one end of the cylinder 77 through a pipe 78. The arrangement is such that when fluid pressure is transmitted through pipe 78 to theleft side of piston 76, the piston is actuated and the lever 72 swung toward the right. This action of the lever is trans mitted to the drum through the dog 71 and ratchet wheel 73 so as to rotate the drum in such direction as to relieve the tension in the metal strip a. Upon release of fluid pressure in pipe 78, however, the lever 72 is free to swing toward the left so as to permit the drum to rotate sufliciently to restore the tension in the metal strip.

In the apparatus shown both pipes 53 and 78 lead from a valve 79 which controls the application and release of fluid pressure thereto. The valve shown comprises a rotary piston 80 fitted in. a casing 81. The casing is supplied with fluid pressure from an appropriate source through a pipe 82, and is open to exhaust through'a port 83. Pipes 53 and 78 lead to opposite sides of the casing. The opposite sides of the piston are cut away, as at 84 and 85. With the valve in the position shown pipe 53 is open to the exhaust port 83 through passage 84 and pipe '78 isopen to the pressure pipe 82 through passage 85. By rotating the valve counter-clockwise thru an angle of ninety degrees, pipe 53 is opened to pressure pipe 82 through passage 84, and pipe78 is opened to exhaust port 83, through passage 85. The piston 80 may be controlled by an appropriate handle 86 fixed thereto. Y

--"In order to heat the metal strip a to the desired bending temperature it isextended through an appropriate oven 87 preferably dicated in Fig. 5. The other It will be noted that this spring is of curved grid-like form and comprises a series of parallel limbs 6 equally spaced.

To form this spring a strip of metal a is extended through the oven 8, one end of the strip being fixed between the end plate 46 and adjacent plug 44, the other end of the strip being connected with the cable 66. A head 31 has been selected having a curvature corresponding to that in the finished spring. The rotary table 16 has been so set that the head 31 extends crosswise of the length of the strip, and the head 31 has been so adjusted in the table that the plug 44 is immediately'beneath the plunger 47. The valve 79 is then adjusted so that fluid pressure is applied through pipe 53 to the plunger 47 so as to force the same downwardly against the plug. Simultaneously the pressure in pipe 78 is released and the drum 67 rotated so as to apply tension to the strip.

The table 16 is then rotated through an angle of one hundred eighty degrees in such direction as to bend or wind the stri about l the plug 44. Fig. 4 illustrates the position of the parts after the first bend has been completed by rotation of the table 16 in a counter-clockwise direction. One of the hammers is then swung so that the head 64 thereof drives the strip against the exposed face of the plug, to insure complete bending of the strip.

The plunger 47 is then raised by manipulation of the valve 79 and the dog 71 actuated to relieve the tension in the strip. A second plug 44 is then inserted in the head 31 against the first plug, so that the material 1 of the strip is confined between these plugs. The head 31 is adjusted longitudinally to bring the new plug beneath the plunger 47. The plunger 47 'is then lowered into clamping engagement with the new plug and the tension again established in the metal strip.

The table is then rotated in the opposite direction through an angle of one hundred eighty degrees causing the strip to be bent or wrapped about the second plu 44 as'inammer is then actuated so that the newly formed leg of the spring is driven against, the exposed face of the second plug.

These steps are repeated, a new plug being added each time, until a spring of the desired dimensions has been formed. It will be noted that before each bending operation, the head 31 is so adjusted in thetable 16 as to position the last inserted plug beneath the plunger 47, and within the axis of rotation of the table. The indexin pin 41 serves to accurately position'the head head 31 being adjusted by the screw 36 and hand wheel 39. The curvature of the head 31 and-the radial disposition of the several plugs 44, results in the production of a spring of the desired contour.

31, theas defined in the appended claims.

I claim 1. An apparatus for bending strips-or rods into zigzag form comprising the combination of an oscillatable head having means for receiving a succession of main drels, means for oscillating said head to bend the strip or rod upon each mandrel successively applied thereto, and means for tensioning the strip or rod during each bending operation.

2. An apparatus for bending strips or rods into zigzag form comprising the combination of an oscillatable head having means for receiving a succession of mandrels, means for oscillating said head to bend the strip or rod upon each mandrel successively applied thereto, andmeans for retaining said rod or strip against lateral movement during each bending operation.

3. An apparatus for bending strips or rods into zigzag form comprising the combination of an oscillatable head having means nation of an oscillatable head having means for receiving a succession of mandrels and for supporting the same with their axes radially disposed about a common center, a support for said head, and means for oscillating said head to bend the strip or rod upon each mandrel successively appliedthereto.

6. An apparatus for bending strips or rods into zigzag form comprising the combination of a support, a member rotatable thereon about a fixed axis, a head adjustably supported on said member and having means for receiving a succesion of mandrels, and means for adjusting said head to place said mandrels successively substantially within said axis.

' 7. In a bending machine the combination of a support, a member rotatable thereon about a fixed axis, a head rockably mounted on saidmember and havingmeans for receiving a succession of mandrels, means for rocking said head to place any of said mandrels substantially within said axis, and

III)

for receiving a succession of mandrels,

' placed.

on said member, said head having means for reeiving a succession of mandrels and for supporting the same in an arcuate series, means for rocking saidhead to place sa d mandrels successively substantially within said axis, and means for rotating said member to bend the work about the mandrel so 9. In a bending machine thecombination of a support, a member rotatable thereon about a fixed axis, a head rockably supported by said member, said head having means for receiving a succession of mandrels and for supporting the same with their axes radially disposed, means for rocking said head to place any of said mandrels within said first mentioned axis, and means for rotating said member to bend the work about the mandrel so placed.

10. In a bending machine the combination of a support, a member rotatable thereon about a fixed axis, a head adjustable thereon,

' said head having means for receiving a succession of mandrels, means for adjusting said head to place said mandrels successively within said axis, means for rotating said member to bend the Work about said mandrels, and means for applying a clamping pressure to said mandrels during the bending operation.

11. In a bending machine the combination of a support, a member rotatable therein, a head adjustably supported on said member and having means for receiving a succession of mandrels, means for adjusting said head, means for rotating said memberto bend the work about said mandrels, successively, and a plunger for exerting a clamping pressure on each mandrel during the bendin operation.

12.- n a bending machine the combina tion of an oscillatablexhead having means means for oscillating said head to bend the work about each mandrel successively applied thereto, and means for retaining said mandrel in said head during each bending operation,

13. In a bending machine the combination of an oscillatable head having means for receiving a succession of mandrels, means for oscillating said head to bend the work about each 'mandrel successively applied each mandrel while the work is being bent.

thereon, meansfor maintaining tension on the work during each bending operation, and means for relieving said clamping pressure and said tension after each bending operation.

15.- In a bending machine the combination of an oscillatable head having means for receiving a succession of mandrels, fluid actuatcd means for applying a clamping pressure. to said mandrels, means for applying tension to the work, fluid actuated means for relieving the tension, and means for controlling both of said fluid actuated 'means. 16. In a bending machine the combination of a head having an arcuate series of openings therein, a series of mandrels adapted to be placed in said openings successively, and means for rotating said head to bend the work about each mandrel successively applied thereto.

17. In a bending machine the combination of a head having an arcuate surface, radially disposed openings in said surface, aseries of mandrels adapted to be placed in said openings successively, and means for bending the" work about each ,mandrel successively inserted in said openings.

18. In a bending machine the combination of a head having an arcuate surface, radially v disposed openings in said surface, a series of mandrels adapted to be placed in said openings successively, each mandrel having f a shoulder cooperating with an adjacent mandrel and said surface to form a work confining space, and means for bending the work about each mandrel successively insert ed in said openings.

In witness whereof, 'I,hereunto subscribe my name this 17th day of February, 1926.

HERMAN E. FRENTZEL. 

